This application claims the benefit of Korean Application No. 99-23946, filed Jun. 24, 1999 in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a magneto-optical head for magneto-optical reading and writing systems, with improved structure associated with a field modulation coil and installation of a miniature objective lens, and a method of manufacturing the same.
2. Description of the Related Art
Magneto-optical reading and writing systems write information onto magneto-optical recording media by magnetic field modulation, and read written information from the media in an optical manner.
Referring to FIG. 1, a common magneto-optical reading and writing system is shown. The magneto-optical reading and writing system includes a swing arm 21 mounted to enable it to pivot relative to a base 10, an actuator 23 for providing a rotary driving force to the swing arm 21, an air-bearing slider 25, attached at one end of the swing arm 21, which flies over a magneto-optical recording medium 1 by hydrodynamics to scan tracks thereof, and a magneto-optical head 30 mounted at the slider 25 to read information optically from the magneto-optical recording medium 1. The magneto-optical head 30 includes an objective lens 31 for focusing a light spot onto the magneto-optical recording medium 1, and coils (not shown) for magnetic field modulation.
Referring to FIGS. 2 and 3, the conventional magneto-optical head 30 of a magneto-optical reading and writing system includes: the objective lens 31, which is installed on the slider 25, for focusing incident laser light onto the magneto-optical recording medium 1; a pair of magnetic pole pieces 33 and 35 mounted parallel to and on respective sides of the slider 25, and also mounted between the objective lens 31 and the surface of the magneto-optical recording medium 1; and first and second coils 37 and 39 are wound around the magnetic pole pieces 33 and 35, respectively. The magnetic pole pieces 33 and 35 are separated from one another, allowing laser light focused by the objective lens 31 to pass through the gap therebetween. The first and second coils 37 and 39 establish horizontal magnetic fields, the orientation of which varies according to the direction of current flowing through the coils 37 and 39, which enables the magneto-optical head 30 to write information onto the magneto-optical recording medium 1.
As previously described, the conventional magneto-optical head 30 has the construction in which the first and second coils 37 and 39 are wound around the magnetic pole pieces 33 and 35 mounted below the objective lens 31 in a horizontal direction. Due to the structure, there are limitations in miniaturizing the magneto-optical head 30, which limits the recording density and performance of near-field recording. In addition, winding the first and second coils 37 and 39 around the magnetic pole pieces 33 and 35, respectively, is ineffective in terms of assembling characteristics, costs and yields, thereby making mass production thereof difficult.
To solve the above problems, it is an object of the present invention to provide a magneto-optical head for magneto-optical reading and writing systems and a method of manufacturing the same, in which a thin film type microcoil for field modulation is formed in a semiconductor fabrication process, so that the magneto-optical head can be miniaturized with improved performance of near-field recording.
It is a further object of the present invention to provide a magneto-optical head for magneto-optical reading and writing systems and a method of manufacturing the same which simplifies the assembling of miniature coils to lower costs and increases yields to enable mass production of the magneto-optical reading and writing systems.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
According to an aspect of the present invention, there is provided a magneto-optical head for a magneto-optical writing and reading system capable of writing information on a magneto-optical recording medium by field modulation and optically reading information from the magneto-optical recording medium, the magneto-optical head being mounted at the end of a slide-arm movable over the magneto-optical recording medium by hydrodynamics, the magneto-optical head comprising: a lens mounted at the end of the slide-arm, for focusing incident light to form a light spot on the magneto-optical recording medium; a coil member including at least two stacked coil layers, and an insulating layer interposed between the two coil layers for electrically insulating the two coil layers from one another, the two stacked coil layers being planar coils with a spiral structure and having electrical contacts for electrical connection therebetween; and a connection member interposed between the lens and the coil member, for connecting the coil member to one side of the lens, facing the magneto-optical recording medium, and for electrically connecting the coil layers to an external power supply.
Preferably, the connection member is solder bumps formed projecting from the uppermost coil layer of the coil member, with a conductive material for electrical connection to the external power supply, the solder bumps adhering to the lens by thermal melting. Preferably, the solder bumps are formed of at least one metal alloy selected from the group consisting of a tin-lead (Snxe2x80x94Pb) alloy, a silver-tin-lead (Agxe2x80x94Snxe2x80x94Pb) alloy and a gold-tin (Auxe2x80x94Sn) alloy.
According to another aspect of the present invention, there is provided a method of manufacturing a magneto-optical head for a magneto-optical writing and reading system capable of writing information on a magneto-optical recording medium by magnetic field modulation and optically reading information from the magneto-optical recording medium, the magneto-optical head being mounted at the end of a slide-arm movable over the magneto-optical recording medium by hydrodynamics, the method comprising: forming a sacrificial layer over a substrate; forming a coil member over the sacrificial layer, the coil member including at least two coil layers and at least one insulating layer; patterning the coil member and the sacrificial layer to form a through hole; forming a plating mold pattern over the uppermost coil layer of the coil member, and plating solder into the plating mold pattern to form solder bumps; preparing a lens having an emitting portion projecting a predetermined length toward the magneto-optical recording medium, the lens for focusing incident light to form a light spot on the magneto-optical recording layer, and coating a metal thin film having a predetermined pattern on the bottom surface of the lens, except on the emitting portion, to form a conductive reflective layer; inserting the emitting portion into the through hole to place the lens on the solder bumps, and heating the assembly to melt the solder bumps and adhere the lens to the coil member; and removing the sacrificial layer to separate the combined lens and coil member from the substrate.
Preferably, forming the coil member comprises: forming a seed layer pattern for plating over the sacrificial layer; depositing a mold over the seed layer pattern to a predetermined thickness, and patterning the mold layer to form a plating mold pattern; plating a metal into the plating mold pattern to form a coil layer having a predetermined thickness; forming an insulating layer over the plating mold pattern and the coil layer; and repeating one or more times the formation of the seed layer, formation of the plating mold pattern, formation of the coil layer and formation of the insulating layer in sequence, to form a stacked multiple coil layer with flatness between every coil layer of the stack.